Special Containment Procedures: Due to the number and distribution of SCP-118, containment of every specimen is impossible. Known SCP-118 Red Zones are to be closed off to all civilian marine vessels and divers under the guise of a military presence or other plausible cover story. Contacts in navies known to operate near SCP-118 Red Zones are to be utilized in order to minimize the passage of military vessels through the Red Zones. If any area within the Red Zone has a depth of less than 1500 meters, the restriction is to be applied to aircraft as well. All human activity in surrounding Yellow Zones is to be monitored, and any non-military vessels or individuals approaching the Red Zone are to be turned away. In the Red and Yellow Zones, protocol TOXIC HARVEST is to be followed to ensure the removal of devices generated by SCP-118. Furthermore, protocol CELL WATCH is to be followed to ensure the early detection of any emerging Red Zones.

Samples of SCP-118 can be stored using standard containment procedures for non-virulent anomalous microbes.

Description: SCP-118 is a species of ocean-dwelling protista that is capable of assembling functional, self initiating, nuclear devices from materials present in ocean water. While SCP-118 is unknown and hence has not been classified by the scientific community, specimens resemble protists of the phylum Euglenophyta but have significantly increased levels of movement speed, nutrient storage capability and resistance to alpha radiation. Specimens of SCP-118 have been found in all of the world's oceans and seas.

When in a survivable salt water environment, specimens of SCP-118 will seek out materials including but not limited to iron, silver, copper, carbon, TNT, and uranium isotopes. When SCP-118 has located a material of interest the material is absorbed into the cell using a method dependent on the size of the material. Single atoms and molecules (mostly substances that are dissolved in the water) are passed through the cellular membrane through specialized protein pumps. Larger particles smaller than the cell itself are ingested through phagocytosis. Larger pieces will have particles torn off through an unknown mechanism, which are then absorbed using the first two methods. This "mining" occurs even in solid and hard substances, such as metal ingots.

Upon reaching a threshold of absorbed materials, specimens of SCP-118 will move towards an "assembly area" on the bottom of the body of the water they are present in and will contribute to the assembly of a nuclear device. The nuclear devices assembled are gun-type fission devices using Uranium-235 as their fissile material. Observation of devices in the process of being assembled show that the process starts with the assembly of a metallic rounded cylindrical casing for the device, followed by the creation of two sub-critical masses of uranium and the conventional explosives to propel them into each other. The mechanism by which SCP-118 enriches harvested uranium is currently unknown. (See Addendum 4). The device is then finished with the assembly of a Uranium-238 tamper where the two uranium masses will collide and the assembly of a trigger mechanism. SCP-118 appears to assemble the necessary components by adding minuscule amounts of material to an (initially) tiny material "seed". Differing atoms and molecules can be added to the same component and assembled components are not necessarily homogeneous. It is currently unknown whether SCP-118 builds on the seed atom by atom or by adding very small sub-micrometer fragments. The mechanism by which SCP-118 attaches new material to the seed seamlessly is unknown. The assembly time depends on the size of the device being assembled, water conditions and mineral availability but observations suggest that 300 days for a medium size device can be considered average.

Once a nuclear device is finished SCP-118 will detonate the device by completing a circuit in the trigger mechanism. Around 90% of the nuclear explosions recorded as a result of SCP-118 have had yields in the 20 to 35 kiloton range, although yields as low as 4 kilotons and up to ███ kilotons have been reported. Aside from cases involving human interference, failure to detonate has never been observed, as all nuclear devices recorded have either been detonated of their own accord or removed from the water prior to completion. Devices constructed by SCP-118 appear to be larger than man-made devices of similar design and yield, presumably due to the neutron moderating effect of the water that separates the uranium masses throughout much of the device's construction. A given assembly area typically has between one and three devices in the process of assembly at any given time, although as many as six at a time has been observed. In zones where multiple devices are being simultaneously assembled, the devices are separated by enough distance to prevent the detonation of one from destroying or setting off the other(s).

While the Foundation is unable to prevent civilians and other organizations from obtaining samples of SCP-118, its superficial similarity to existing species, few numbers (relative to all oceanic protista), lack of anomalous behavior outside material rich bodies of water, and the Foundation's standard monitoring of scientific studies at risk of uncovering information about anomalous biological species ensures that the chance of SCP-118's true nature being determined through cell samples is minimal.

There are currently six different active SCP-118 assembly areas known to the Foundation. While the natural disappearance of an assembly area has been observed, the current consensus among researchers assigned to SCP-118 is that elimination of assembly areas without massively noticeable effects is currently unfeasible (See Experiment Log 118 - Gamma for details). Thus, containment is to be established at SCP-118's assembly areas, to be designated "Red Zones", and surrounding "Yellow Zones". Furthermore, areas with elevated concentrations of SCP-118, "Zones of Interest", are to be monitored for signs of assembly areas.

RZ - 7
Location: [REDACTED]
Coordinates: [REDACTED]
Zone commander: Captain ████████
Note: Red Zone lies within ████████ city limits. This, combined with the shallow average depth of Red Zone, the heavy shipping traffic in the area, the ongoing tensions between ██████ and ██████, a nuclear power, and the presence of Foundation personnel and facilities in the city makes a nuclear detonation in this Red Zone unacceptable. In addition, heavy ship traffic through the area and heavy air traffic above the city make restricting access for any long period of time impractical.

Addendum-118-1: Following the USS ████████ Incident, the exclusion radius used when drawing red zones had been increased. Containment protocol TOXIC HARVEST has been updated.

Addendum-118-2: With the signing of the Partial Test Ban Treaty and growing number and capability of nuclear detonation detection methods in use, the consequences of nuclear detonations caused by SCP-118 have increased. Containment protocols have been revised in light of these facts.

Addendum-118-3: Due to the significant cost of containing SCP-118 Red Zones, the O-5 council has requested trials on possible methods to eliminate SCP-118 assembly areas.

Introduction: Researchers with access to the files on SCP-118 are allowed to submit proposals to eradicate an SCP-118 assembly area with acceptable levels of collateral damage. The ones approved by TOXIC HARVEST command and the O5 council will be carried out. Trials are to be performed in Red Zone █.

Proposal: Sterilization of unfinished nuclear device and immediate surroundings using a UV light emitter.Approval: ApprovedResult: Area around unfinished warhead initially free of micro-organisms, however SCP-118 concentration returned to normal levels within an hour.Non-sustained sterilization of sites seems ineffectual. Any method we come up with will have to keep the Red Zone, or at least the sea floor of it, free of SCP-118 for an extended period of time. -Dr Brant

Proposal: Depth charge bombardment of ocean floor to break up under-assembly devicesApproval: DeniedResult: N/AAside from the fact this would break our naval budget, the chances of triggering the conventional explosive in the devices and causing a "fizzle" is too high. It would also make our activities even more detectable with hydrophones. -Dr Klaus

Proposal: "Sweeping" of ocean using a Cobalt-60 powered directional gamma ray emitter.Approval: ApprovedResult: While procedure resulted in the sterilization of "swept" area, procedure was far too slow to sterilize entire Red Zone before specimens returned. Keeping entire Red Zone sterile would require impractical numbers of emitters and vessels.While it's a shame the device can not get rid of the Red Zones for us, I think it can be of use to our device recovery teams. The gamma rays can sterilize the devices we recover to prevent undesired detonations during the recovery of almost complete devices. The gamma rays can also penetrate into areas where our current chemical and UV sterilization methods can't reach -Captain Thomson (RZ-3 Zone Commander)

Proposal: A plastic membrane to block access to ocean floor at Red ZoneApproval: Proof of concept on one under-assembly warhead approvedResult: First attempt was unable to acquire a water-tight seal around warhead. Membrane in second attempt was too fragile for ocean conditions and was torn off its moors. Third membrane, manufactured using a thicker and sturdier design, had hundreds of micro tears ripped in it within hours, possibly due to SCP-118's "mining" action.Not surprising, considering that SCP-118 has been known to wear through the casings of old artillery shells to harvest the explosives within. We had hoped that cutting off the assembly area would work better than cutting off the raw materials. -Dr. Klaus

Proposal: Compound ██████ pumped to ocean floor.Note: Proposed by Dr. ██████████, former researcher for SCP-118 currently working at Bio Research Site ██'s Chemical Research Division. Tests confirm that compound is lethal to SCP-118, remains concentrated at bottom of water, and degrades into relatively harmless chemicals in water over a period of 15 hours.Approval: ApprovedResult: Over one week, SCP-118 concentrations on ocean floor fell to 3% of previous levels. No signs of progress observed on two known uncompleted nuclear devices in Red Zone. However, 100 days after the start of the experiment an under assembly nuclear device was detected 60 km North of the Red Zone. Measurements in the area indicated vastly elevated levels of SCP-118 and the area around discovery was reclassified as a Red Zone. Furthermore, the unexpected breakdown of Compound ██████ by certain species of oceanic bacteria resulted in toxic byproducts that caused a noticeable die-off of fish in treated zone. Upon stoppage of experiment Red Zone was observed to gradually "migrate" back to former location.It seems that making a Red Zone non-viable served only to move SCP-118's assembly areas to a new location. Nevertheless, perhaps if we can improve Compound ██████ or find a new one whose application is more subtle we can move Red Zones into areas away from areas of human habitation or commercial activity. -Dr. ██████████

Proposal: Use of SCP-████ via ████████████████████████████████████.Approval: DeniedResult: N/ASCP-████ has classified properties that preclude its use in such a manner. -O5-5

Conclusion: Due to increased media attention to areas around Red Zone █ due to aftermath of the application of Compound ██████ and the lack of proposals without high risks of substantial collateral damage, testing in Red Zone █ has been suspended.

Addendum-118-4 (Level 4 Clearance required):

Our research has determined SCP-118 enriches uranium by exploiting the fact that U-235 has a slightly greater preference for a high oxidation state than U-238. SCP-118 specimens which have harvested large amounts of uranium and are near assembly areas appear to develop specialized organelles resembling a series of thousands of vacuole-like chambers with mitochondria-like organelles within them, responsible for catalyzing reduction and oxidation reactions. In a given chamber, uranium is repeatedly reduced and oxidized. Compounds with uranium in higher oxidation states are transferred up the "chain" of chambers while compounds with lower oxidation states are transferred down the chain. This results in a small amount of highly enriched uranium at the very end of the chain.

Researchers and engineers at Research Sector █ have managed to create a prototype uranium enrichment device based on the principles employed by SCP-118. While the prototype was unable to produce weapons-grade uranium without using unreasonable amounts of time, it was successful in producing reactor-grade uranium, albeit at significantly greater cost than conventional methods. Despite its current limitations, the idea shows promise and I have forwarded our findings to the relevant front companies.